/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "OpenGLRenderer"
// The highest z value can't be higher than (CASTER_Z_CAP_RATIO * light.z)
#define CASTER_Z_CAP_RATIO 0.95f
// When there is no umbra, then just fake the umbra using
// centroid * (1 - FAKE_UMBRA_SIZE_RATIO) + outline * FAKE_UMBRA_SIZE_RATIO
#define FAKE_UMBRA_SIZE_RATIO 0.05f
// When the polygon is about 90 vertices, the penumbra + umbra can reach 270 rays.
// That is consider pretty fine tessllated polygon so far.
// This is just to prevent using too much some memory when edge slicing is not
// needed any more.
#define FINE_TESSELLATED_POLYGON_RAY_NUMBER 270
/**
* Extra vertices for the corner for smoother corner.
* Only for outer loop.
* Note that we use such extra memory to avoid an extra loop.
*/
// For half circle, we could add EXTRA_VERTEX_PER_PI vertices.
// Set to 1 if we don't want to have any.
#define SPOT_EXTRA_CORNER_VERTEX_PER_PI 18
// For the whole polygon, the sum of all the deltas b/t normals is 2 * M_PI,
// therefore, the maximum number of extra vertices will be twice bigger.
#define SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER (2 * SPOT_EXTRA_CORNER_VERTEX_PER_PI)
// For each RADIANS_DIVISOR, we would allocate one more vertex b/t the normals.
#define SPOT_CORNER_RADIANS_DIVISOR (M_PI / SPOT_EXTRA_CORNER_VERTEX_PER_PI)
#include <math.h>
#include <stdlib.h>
#include <utils/Log.h>
#include "ShadowTessellator.h"
#include "SpotShadow.h"
#include "Vertex.h"
#include "utils/MathUtils.h"
// TODO: After we settle down the new algorithm, we can remove the old one and
// its utility functions.
// Right now, we still need to keep it for comparison purpose and future expansion.
namespace android {
namespace uirenderer {
static const double EPSILON = 1e-7;
/**
* For each polygon's vertex, the light center will project it to the receiver
* as one of the outline vertex.
* For each outline vertex, we need to store the position and normal.
* Normal here is defined against the edge by the current vertex and the next vertex.
*/
struct OutlineData {
Vector2 position;
Vector2 normal;
float radius;
};
/**
* For each vertex, we need to keep track of its angle, whether it is penumbra or
* umbra, and its corresponding vertex index.
*/
struct SpotShadow::VertexAngleData {
// The angle to the vertex from the centroid.
float mAngle;
// True is the vertex comes from penumbra, otherwise it comes from umbra.
bool mIsPenumbra;
// The index of the vertex described by this data.
int mVertexIndex;
void set(float angle, bool isPenumbra, int index) {
mAngle = angle;
mIsPenumbra = isPenumbra;
mVertexIndex = index;
}
};
/**
* Calculate the angle between and x and a y coordinate.
* The atan2 range from -PI to PI.
*/
static float angle(const Vector2& point, const Vector2& center) {
return atan2(point.y - center.y, point.x - center.x);
}
/**
* Calculate the intersection of a ray with the line segment defined by two points.
*
* Returns a negative value in error conditions.
* @param rayOrigin The start of the ray
* @param dx The x vector of the ray
* @param dy The y vector of the ray
* @param p1 The first point defining the line segment
* @param p2 The second point defining the line segment
* @return The distance along the ray if it intersects with the line segment, negative if otherwise
*/
static float rayIntersectPoints(const Vector2& rayOrigin, float dx, float dy,
const Vector2& p1, const Vector2& p2) {
// The math below is derived from solving this formula, basically the
// intersection point should stay on both the ray and the edge of (p1, p2).
// solve([p1x+t*(p2x-p1x)=dx*t2+px,p1y+t*(p2y-p1y)=dy*t2+py],[t,t2]);
double divisor = (dx * (p1.y - p2.y) + dy * p2.x - dy * p1.x);
if (divisor == 0) return -1.0f; // error, invalid divisor
#if DEBUG_SHADOW
double interpVal = (dx * (p1.y - rayOrigin.y) + dy * rayOrigin.x - dy * p1.x) / divisor;
if (interpVal < 0 || interpVal > 1) {
ALOGW("rayIntersectPoints is hitting outside the segment %f", interpVal);
}
#endif
double distance = (p1.x * (rayOrigin.y - p2.y) + p2.x * (p1.y - rayOrigin.y) +
rayOrigin.x * (p2.y - p1.y)) / divisor;
return distance; // may be negative in error cases
}
/**
* Sort points by their X coordinates
*
* @param points the points as a Vector2 array.
* @param pointsLength the number of vertices of the polygon.
*/
void SpotShadow::xsort(Vector2* points, int pointsLength) {
quicksortX(points, 0, pointsLength - 1);
}
/**
* compute the convex hull of a collection of Points
*
* @param points the points as a Vector2 array.
* @param pointsLength the number of vertices of the polygon.
* @param retPoly pre allocated array of floats to put the vertices
* @return the number of points in the polygon 0 if no intersection
*/
int SpotShadow::hull(Vector2* points, int pointsLength, Vector2* retPoly) {
xsort(points, pointsLength);
int n = pointsLength;
Vector2 lUpper[n];
lUpper[0] = points[0];
lUpper[1] = points[1];
int lUpperSize = 2;
for (int i = 2; i < n; i++) {
lUpper[lUpperSize] = points[i];
lUpperSize++;
while (lUpperSize > 2 && !ccw(
lUpper[lUpperSize - 3].x, lUpper[lUpperSize - 3].y,
lUpper[lUpperSize - 2].x, lUpper[lUpperSize - 2].y,
lUpper[lUpperSize - 1].x, lUpper[lUpperSize - 1].y)) {
// Remove the middle point of the three last
lUpper[lUpperSize - 2].x = lUpper[lUpperSize - 1].x;
lUpper[lUpperSize - 2].y = lUpper[lUpperSize - 1].y;
lUpperSize--;
}
}
Vector2 lLower[n];
lLower[0] = points[n - 1];
lLower[1] = points[n - 2];
int lLowerSize = 2;
for (int i = n - 3; i >= 0; i--) {
lLower[lLowerSize] = points[i];
lLowerSize++;
while (lLowerSize > 2 && !ccw(
lLower[lLowerSize - 3].x, lLower[lLowerSize - 3].y,
lLower[lLowerSize - 2].x, lLower[lLowerSize - 2].y,
lLower[lLowerSize - 1].x, lLower[lLowerSize - 1].y)) {
// Remove the middle point of the three last
lLower[lLowerSize - 2] = lLower[lLowerSize - 1];
lLowerSize--;
}
}
// output points in CW ordering
const int total = lUpperSize + lLowerSize - 2;
int outIndex = total - 1;
for (int i = 0; i < lUpperSize; i++) {
retPoly[outIndex] = lUpper[i];
outIndex--;
}
for (int i = 1; i < lLowerSize - 1; i++) {
retPoly[outIndex] = lLower[i];
outIndex--;
}
// TODO: Add test harness which verify that all the points are inside the hull.
return total;
}
/**
* Test whether the 3 points form a counter clockwise turn.
*
* @return true if a right hand turn
*/
bool SpotShadow::ccw(double ax, double ay, double bx, double by,
double cx, double cy) {
return (bx - ax) * (cy - ay) - (by - ay) * (cx - ax) > EPSILON;
}
/**
* Calculates the intersection of poly1 with poly2 and put in poly2.
* Note that both poly1 and poly2 must be in CW order already!
*
* @param poly1 The 1st polygon, as a Vector2 array.
* @param poly1Length The number of vertices of 1st polygon.
* @param poly2 The 2nd and output polygon, as a Vector2 array.
* @param poly2Length The number of vertices of 2nd polygon.
* @return number of vertices in output polygon as poly2.
*/
int SpotShadow::intersection(const Vector2* poly1, int poly1Length,
Vector2* poly2, int poly2Length) {
#if DEBUG_SHADOW
if (!ShadowTessellator::isClockwise(poly1, poly1Length)) {
ALOGW("Poly1 is not clockwise! Intersection is wrong!");
}
if (!ShadowTessellator::isClockwise(poly2, poly2Length)) {
ALOGW("Poly2 is not clockwise! Intersection is wrong!");
}
#endif
Vector2 poly[poly1Length * poly2Length + 2];
int count = 0;
int pcount = 0;
// If one vertex from one polygon sits inside another polygon, add it and
// count them.
for (int i = 0; i < poly1Length; i++) {
if (testPointInsidePolygon(poly1[i], poly2, poly2Length)) {
poly[count] = poly1[i];
count++;
pcount++;
}
}
int insidePoly2 = pcount;
for (int i = 0; i < poly2Length; i++) {
if (testPointInsidePolygon(poly2[i], poly1, poly1Length)) {
poly[count] = poly2[i];
count++;
}
}
int insidePoly1 = count - insidePoly2;
// If all vertices from poly1 are inside poly2, then just return poly1.
if (insidePoly2 == poly1Length) {
memcpy(poly2, poly1, poly1Length * sizeof(Vector2));
return poly1Length;
}
// If all vertices from poly2 are inside poly1, then just return poly2.
if (insidePoly1 == poly2Length) {
return poly2Length;
}
// Since neither polygon fully contain the other one, we need to add all the
// intersection points.
Vector2 intersection = {0, 0};
for (int i = 0; i < poly2Length; i++) {
for (int j = 0; j < poly1Length; j++) {
int poly2LineStart = i;
int poly2LineEnd = ((i + 1) % poly2Length);
int poly1LineStart = j;
int poly1LineEnd = ((j + 1) % poly1Length);
bool found = lineIntersection(
poly2[poly2LineStart].x, poly2[poly2LineStart].y,
poly2[poly2LineEnd].x, poly2[poly2LineEnd].y,
poly1[poly1LineStart].x, poly1[poly1LineStart].y,
poly1[poly1LineEnd].x, poly1[poly1LineEnd].y,
intersection);
if (found) {
poly[count].x = intersection.x;
poly[count].y = intersection.y;
count++;
} else {
Vector2 delta = poly2[i] - poly1[j];
if (delta.lengthSquared() < EPSILON) {
poly[count] = poly2[i];
count++;
}
}
}
}
if (count == 0) {
return 0;
}
// Sort the result polygon around the center.
Vector2 center = {0.0f, 0.0f};
for (int i = 0; i < count; i++) {
center += poly[i];
}
center /= count;
sort(poly, count, center);
#if DEBUG_SHADOW
// Since poly2 is overwritten as the result, we need to save a copy to do
// our verification.
Vector2 oldPoly2[poly2Length];
int oldPoly2Length = poly2Length;
memcpy(oldPoly2, poly2, sizeof(Vector2) * poly2Length);
#endif
// Filter the result out from poly and put it into poly2.
poly2[0] = poly[0];
int lastOutputIndex = 0;
for (int i = 1; i < count; i++) {
Vector2 delta = poly[i] - poly2[lastOutputIndex];
if (delta.lengthSquared() >= EPSILON) {
poly2[++lastOutputIndex] = poly[i];
} else {
// If the vertices are too close, pick the inner one, because the
// inner one is more likely to be an intersection point.
Vector2 delta1 = poly[i] - center;
Vector2 delta2 = poly2[lastOutputIndex] - center;
if (delta1.lengthSquared() < delta2.lengthSquared()) {
poly2[lastOutputIndex] = poly[i];
}
}
}
int resultLength = lastOutputIndex + 1;
#if DEBUG_SHADOW
testConvex(poly2, resultLength, "intersection");
testConvex(poly1, poly1Length, "input poly1");
testConvex(oldPoly2, oldPoly2Length, "input poly2");
testIntersection(poly1, poly1Length, oldPoly2, oldPoly2Length, poly2, resultLength);
#endif
return resultLength;
}
/**
* Sort points about a center point
*
* @param poly The in and out polyogon as a Vector2 array.
* @param polyLength The number of vertices of the polygon.
* @param center the center ctr[0] = x , ctr[1] = y to sort around.
*/
void SpotShadow::sort(Vector2* poly, int polyLength, const Vector2& center) {
quicksortCirc(poly, 0, polyLength - 1, center);
}
/**
* Swap points pointed to by i and j
*/
void SpotShadow::swap(Vector2* points, int i, int j) {
Vector2 temp = points[i];
points[i] = points[j];
points[j] = temp;
}
/**
* quick sort implementation about the center.
*/
void SpotShadow::quicksortCirc(Vector2* points, int low, int high,
const Vector2& center) {
int i = low, j = high;
int p = low + (high - low) / 2;
float pivot = angle(points[p], center);
while (i <= j) {
while (angle(points[i], center) > pivot) {
i++;
}
while (angle(points[j], center) < pivot) {
j--;
}
if (i <= j) {
swap(points, i, j);
i++;
j--;
}
}
if (low < j) quicksortCirc(points, low, j, center);
if (i < high) quicksortCirc(points, i, high, center);
}
/**
* Sort points by x axis
*
* @param points points to sort
* @param low start index
* @param high end index
*/
void SpotShadow::quicksortX(Vector2* points, int low, int high) {
int i = low, j = high;
int p = low + (high - low) / 2;
float pivot = points[p].x;
while (i <= j) {
while (points[i].x < pivot) {
i++;
}
while (points[j].x > pivot) {
j--;
}
if (i <= j) {
swap(points, i, j);
i++;
j--;
}
}
if (low < j) quicksortX(points, low, j);
if (i < high) quicksortX(points, i, high);
}
/**
* Test whether a point is inside the polygon.
*
* @param testPoint the point to test
* @param poly the polygon
* @return true if the testPoint is inside the poly.
*/
bool SpotShadow::testPointInsidePolygon(const Vector2 testPoint,
const Vector2* poly, int len) {
bool c = false;
double testx = testPoint.x;
double testy = testPoint.y;
for (int i = 0, j = len - 1; i < len; j = i++) {
double startX = poly[j].x;
double startY = poly[j].y;
double endX = poly[i].x;
double endY = poly[i].y;
if (((endY > testy) != (startY > testy))
&& (testx < (startX - endX) * (testy - endY)
/ (startY - endY) + endX)) {
c = !c;
}
}
return c;
}
/**
* Make the polygon turn clockwise.
*
* @param polygon the polygon as a Vector2 array.
* @param len the number of points of the polygon
*/
void SpotShadow::makeClockwise(Vector2* polygon, int len) {
if (polygon == 0 || len == 0) {
return;
}
if (!ShadowTessellator::isClockwise(polygon, len)) {
reverse(polygon, len);
}
}
/**
* Reverse the polygon
*
* @param polygon the polygon as a Vector2 array
* @param len the number of points of the polygon
*/
void SpotShadow::reverse(Vector2* polygon, int len) {
int n = len / 2;
for (int i = 0; i < n; i++) {
Vector2 tmp = polygon[i];
int k = len - 1 - i;
polygon[i] = polygon[k];
polygon[k] = tmp;
}
}
/**
* Intersects two lines in parametric form. This function is called in a tight
* loop, and we need double precision to get things right.
*
* @param x1 the x coordinate point 1 of line 1
* @param y1 the y coordinate point 1 of line 1
* @param x2 the x coordinate point 2 of line 1
* @param y2 the y coordinate point 2 of line 1
* @param x3 the x coordinate point 1 of line 2
* @param y3 the y coordinate point 1 of line 2
* @param x4 the x coordinate point 2 of line 2
* @param y4 the y coordinate point 2 of line 2
* @param ret the x,y location of the intersection
* @return true if it found an intersection
*/
inline bool SpotShadow::lineIntersection(double x1, double y1, double x2, double y2,
double x3, double y3, double x4, double y4, Vector2& ret) {
double d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
if (d == 0.0) return false;
double dx = (x1 * y2 - y1 * x2);
double dy = (x3 * y4 - y3 * x4);
double x = (dx * (x3 - x4) - (x1 - x2) * dy) / d;
double y = (dx * (y3 - y4) - (y1 - y2) * dy) / d;
// The intersection should be in the middle of the point 1 and point 2,
// likewise point 3 and point 4.
if (((x - x1) * (x - x2) > EPSILON)
|| ((x - x3) * (x - x4) > EPSILON)
|| ((y - y1) * (y - y2) > EPSILON)
|| ((y - y3) * (y - y4) > EPSILON)) {
// Not interesected
return false;
}
ret.x = x;
ret.y = y;
return true;
}
/**
* Compute a horizontal circular polygon about point (x , y , height) of radius
* (size)
*
* @param points number of the points of the output polygon.
* @param lightCenter the center of the light.
* @param size the light size.
* @param ret result polygon.
*/
void SpotShadow::computeLightPolygon(int points, const Vector3& lightCenter,
float size, Vector3* ret) {
// TODO: Caching all the sin / cos values and store them in a look up table.
for (int i = 0; i < points; i++) {
double angle = 2 * i * M_PI / points;
ret[i].x = cosf(angle) * size + lightCenter.x;
ret[i].y = sinf(angle) * size + lightCenter.y;
ret[i].z = lightCenter.z;
}
}
/**
* From light center, project one vertex to the z=0 surface and get the outline.
*
* @param outline The result which is the outline position.
* @param lightCenter The center of light.
* @param polyVertex The input polygon's vertex.
*
* @return float The ratio of (polygon.z / light.z - polygon.z)
*/
float SpotShadow::projectCasterToOutline(Vector2& outline,
const Vector3& lightCenter, const Vector3& polyVertex) {
float lightToPolyZ = lightCenter.z - polyVertex.z;
float ratioZ = CASTER_Z_CAP_RATIO;
if (lightToPolyZ != 0) {
// If any caster's vertex is almost above the light, we just keep it as 95%
// of the height of the light.
ratioZ = MathUtils::clamp(polyVertex.z / lightToPolyZ, 0.0f, CASTER_Z_CAP_RATIO);
}
outline.x = polyVertex.x - ratioZ * (lightCenter.x - polyVertex.x);
outline.y = polyVertex.y - ratioZ * (lightCenter.y - polyVertex.y);
return ratioZ;
}
/**
* Generate the shadow spot light of shape lightPoly and a object poly
*
* @param isCasterOpaque whether the caster is opaque
* @param lightCenter the center of the light
* @param lightSize the radius of the light
* @param poly x,y,z vertexes of a convex polygon that occludes the light source
* @param polyLength number of vertexes of the occluding polygon
* @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return
* empty strip if error.
*/
void SpotShadow::createSpotShadow(bool isCasterOpaque, const Vector3& lightCenter,
float lightSize, const Vector3* poly, int polyLength, const Vector3& polyCentroid,
VertexBuffer& shadowTriangleStrip) {
if (CC_UNLIKELY(lightCenter.z <= 0)) {
ALOGW("Relative Light Z is not positive. No spot shadow!");
return;
}
if (CC_UNLIKELY(polyLength < 3)) {
#if DEBUG_SHADOW
ALOGW("Invalid polygon length. No spot shadow!");
#endif
return;
}
OutlineData outlineData[polyLength];
Vector2 outlineCentroid;
// Calculate the projected outline for each polygon's vertices from the light center.
//
// O Light
// /
// /
// . Polygon vertex
// /
// /
// O Outline vertices
//
// Ratio = (Poly - Outline) / (Light - Poly)
// Outline.x = Poly.x - Ratio * (Light.x - Poly.x)
// Outline's radius / Light's radius = Ratio
// Compute the last outline vertex to make sure we can get the normal and outline
// in one single loop.
projectCasterToOutline(outlineData[polyLength - 1].position, lightCenter,
poly[polyLength - 1]);
// Take the outline's polygon, calculate the normal for each outline edge.
int currentNormalIndex = polyLength - 1;
int nextNormalIndex = 0;
for (int i = 0; i < polyLength; i++) {
float ratioZ = projectCasterToOutline(outlineData[i].position,
lightCenter, poly[i]);
outlineData[i].radius = ratioZ * lightSize;
outlineData[currentNormalIndex].normal = ShadowTessellator::calculateNormal(
outlineData[currentNormalIndex].position,
outlineData[nextNormalIndex].position);
currentNormalIndex = (currentNormalIndex + 1) % polyLength;
nextNormalIndex++;
}
projectCasterToOutline(outlineCentroid, lightCenter, polyCentroid);
int penumbraIndex = 0;
// Then each polygon's vertex produce at minmal 2 penumbra vertices.
// Since the size can be dynamic here, we keep track of the size and update
// the real size at the end.
int allocatedPenumbraLength = 2 * polyLength + SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER;
Vector2 penumbra[allocatedPenumbraLength];
int totalExtraCornerSliceNumber = 0;
Vector2 umbra[polyLength];
// When centroid is covered by all circles from outline, then we consider
// the umbra is invalid, and we will tune down the shadow strength.
bool hasValidUmbra = true;
// We need the minimal of RaitoVI to decrease the spot shadow strength accordingly.
float minRaitoVI = FLT_MAX;
for (int i = 0; i < polyLength; i++) {
// Generate all the penumbra's vertices only using the (outline vertex + normal * radius)
// There is no guarantee that the penumbra is still convex, but for
// each outline vertex, it will connect to all its corresponding penumbra vertices as
// triangle fans. And for neighber penumbra vertex, it will be a trapezoid.
//
// Penumbra Vertices marked as Pi
// Outline Vertices marked as Vi
// (P3)
// (P2) | ' (P4)
// (P1)' | | '
// ' | | '
// (P0) ------------------------------------------------(P5)
// | (V0) |(V1)
// | |
// | |
// | |
// | |
// | |
// | |
// | |
// | |
// (V3)-----------------------------------(V2)
int preNormalIndex = (i + polyLength - 1) % polyLength;
const Vector2& previousNormal = outlineData[preNormalIndex].normal;
const Vector2& currentNormal = outlineData[i].normal;
// Depending on how roundness we want for each corner, we can subdivide
// further here and/or introduce some heuristic to decide how much the
// subdivision should be.
int currentExtraSliceNumber = ShadowTessellator::getExtraVertexNumber(
previousNormal, currentNormal, SPOT_CORNER_RADIANS_DIVISOR);
int currentCornerSliceNumber = 1 + currentExtraSliceNumber;
totalExtraCornerSliceNumber += currentExtraSliceNumber;
#if DEBUG_SHADOW
ALOGD("currentExtraSliceNumber should be %d", currentExtraSliceNumber);
ALOGD("currentCornerSliceNumber should be %d", currentCornerSliceNumber);
ALOGD("totalCornerSliceNumber is %d", totalExtraCornerSliceNumber);
#endif
if (CC_UNLIKELY(totalExtraCornerSliceNumber > SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER)) {
currentCornerSliceNumber = 1;
}
for (int k = 0; k <= currentCornerSliceNumber; k++) {
Vector2 avgNormal =
(previousNormal * (currentCornerSliceNumber - k) + currentNormal * k) /
currentCornerSliceNumber;
avgNormal.normalize();
penumbra[penumbraIndex++] = outlineData[i].position +
avgNormal * outlineData[i].radius;
}
// Compute the umbra by the intersection from the outline's centroid!
//
// (V) ------------------------------------
// | ' |
// | ' |
// | ' (I) |
// | ' |
// | ' (C) |
// | |
// | |
// | |
// | |
// ------------------------------------
//
// Connect a line b/t the outline vertex (V) and the centroid (C), it will
// intersect with the outline vertex's circle at point (I).
// Now, ratioVI = VI / VC, ratioIC = IC / VC
// Then the intersetion point can be computed as Ixy = Vxy * ratioIC + Cxy * ratioVI;
//
// When all of the outline circles cover the the outline centroid, (like I is
// on the other side of C), there is no real umbra any more, so we just fake
// a small area around the centroid as the umbra, and tune down the spot
// shadow's umbra strength to simulate the effect the whole shadow will
// become lighter in this case.
// The ratio can be simulated by using the inverse of maximum of ratioVI for
// all (V).
float distOutline = (outlineData[i].position - outlineCentroid).length();
if (CC_UNLIKELY(distOutline == 0)) {
// If the outline has 0 area, then there is no spot shadow anyway.
ALOGW("Outline has 0 area, no spot shadow!");
return;
}
float ratioVI = outlineData[i].radius / distOutline;
minRaitoVI = MathUtils::min(minRaitoVI, ratioVI);
if (ratioVI >= (1 - FAKE_UMBRA_SIZE_RATIO)) {
ratioVI = (1 - FAKE_UMBRA_SIZE_RATIO);
}
// When we know we don't have valid umbra, don't bother to compute the
// values below. But we can't skip the loop yet since we want to know the
// maximum ratio.
float ratioIC = 1 - ratioVI;
umbra[i] = outlineData[i].position * ratioIC + outlineCentroid * ratioVI;
}
hasValidUmbra = (minRaitoVI <= 1.0);
float shadowStrengthScale = 1.0;
if (!hasValidUmbra) {
#if DEBUG_SHADOW
ALOGW("The object is too close to the light or too small, no real umbra!");
#endif
for (int i = 0; i < polyLength; i++) {
umbra[i] = outlineData[i].position * FAKE_UMBRA_SIZE_RATIO +
outlineCentroid * (1 - FAKE_UMBRA_SIZE_RATIO);
}
shadowStrengthScale = 1.0 / minRaitoVI;
}
int penumbraLength = penumbraIndex;
int umbraLength = polyLength;
#if DEBUG_SHADOW
ALOGD("penumbraLength is %d , allocatedPenumbraLength %d", penumbraLength, allocatedPenumbraLength);
dumpPolygon(poly, polyLength, "input poly");
dumpPolygon(penumbra, penumbraLength, "penumbra");
dumpPolygon(umbra, umbraLength, "umbra");
ALOGD("hasValidUmbra is %d and shadowStrengthScale is %f", hasValidUmbra, shadowStrengthScale);
#endif
// The penumbra and umbra needs to be in convex shape to keep consistency
// and quality.
// Since we are still shooting rays to penumbra, it needs to be convex.
// Umbra can be represented as a fan from the centroid, but visually umbra
// looks nicer when it is convex.
Vector2 finalUmbra[umbraLength];
Vector2 finalPenumbra[penumbraLength];
int finalUmbraLength = hull(umbra, umbraLength, finalUmbra);
int finalPenumbraLength = hull(penumbra, penumbraLength, finalPenumbra);
generateTriangleStrip(isCasterOpaque, shadowStrengthScale, finalPenumbra,
finalPenumbraLength, finalUmbra, finalUmbraLength, poly, polyLength,
shadowTriangleStrip, outlineCentroid);
}
/**
* Converts a polygon specified with CW vertices into an array of distance-from-centroid values.
*
* Returns false in error conditions
*
* @param poly Array of vertices. Note that these *must* be CW.
* @param polyLength The number of vertices in the polygon.
* @param polyCentroid The centroid of the polygon, from which rays will be cast
* @param rayDist The output array for the calculated distances, must be SHADOW_RAY_COUNT in size
*/
bool convertPolyToRayDist(const Vector2* poly, int polyLength, const Vector2& polyCentroid,
float* rayDist) {
const int rays = SHADOW_RAY_COUNT;
const float step = M_PI * 2 / rays;
const Vector2* lastVertex = &(poly[polyLength - 1]);
float startAngle = angle(*lastVertex, polyCentroid);
// Start with the ray that's closest to and less than startAngle
int rayIndex = floor((startAngle - EPSILON) / step);
rayIndex = (rayIndex + rays) % rays; // ensure positive
for (int polyIndex = 0; polyIndex < polyLength; polyIndex++) {
/*
* For a given pair of vertices on the polygon, poly[i-1] and poly[i], the rays that
* intersect these will be those that are between the two angles from the centroid that the
* vertices define.
*
* Because the polygon vertices are stored clockwise, the closest ray with an angle
* *smaller* than that defined by angle(poly[i], centroid) will be the first ray that does
* not intersect with poly[i-1], poly[i].
*/
float currentAngle = angle(poly[polyIndex], polyCentroid);
// find first ray that will not intersect the line segment poly[i-1] & poly[i]
int firstRayIndexOnNextSegment = floor((currentAngle - EPSILON) / step);
firstRayIndexOnNextSegment = (firstRayIndexOnNextSegment + rays) % rays; // ensure positive
// Iterate through all rays that intersect with poly[i-1], poly[i] line segment.
// This may be 0 rays.
while (rayIndex != firstRayIndexOnNextSegment) {
float distanceToIntersect = rayIntersectPoints(polyCentroid,
cos(rayIndex * step),
sin(rayIndex * step),
*lastVertex, poly[polyIndex]);
if (distanceToIntersect < 0) {
#if DEBUG_SHADOW
ALOGW("ERROR: convertPolyToRayDist failed");
#endif
return false; // error case, abort
}
rayDist[rayIndex] = distanceToIntersect;
rayIndex = (rayIndex - 1 + rays) % rays;
}
lastVertex = &poly[polyIndex];
}
return true;
}
int SpotShadow::calculateOccludedUmbra(const Vector2* umbra, int umbraLength,
const Vector3* poly, int polyLength, Vector2* occludedUmbra) {
// Occluded umbra area is computed as the intersection of the projected 2D
// poly and umbra.
for (int i = 0; i < polyLength; i++) {
occludedUmbra[i].x = poly[i].x;
occludedUmbra[i].y = poly[i].y;
}
// Both umbra and incoming polygon are guaranteed to be CW, so we can call
// intersection() directly.
return intersection(umbra, umbraLength,
occludedUmbra, polyLength);
}
/**
* This is only for experimental purpose.
* After intersections are calculated, we could smooth the polygon if needed.
* So far, we don't think it is more appealing yet.
*
* @param level The level of smoothness.
* @param rays The total number of rays.
* @param rayDist (In and Out) The distance for each ray.
*
*/
void SpotShadow::smoothPolygon(int level, int rays, float* rayDist) {
for (int k = 0; k < level; k++) {
for (int i = 0; i < rays; i++) {
float p1 = rayDist[(rays - 1 + i) % rays];
float p2 = rayDist[i];
float p3 = rayDist[(i + 1) % rays];
rayDist[i] = (p1 + p2 * 2 + p3) / 4;
}
}
}
/**
* Generate a array of the angleData for either umbra or penumbra vertices.
*
* This array will be merged and used to guide where to shoot the rays, in clockwise order.
*
* @param angleDataList The result array of angle data.
*
* @return int The maximum angle's index in the array.
*/
int SpotShadow::setupAngleList(VertexAngleData* angleDataList,
int polyLength, const Vector2* polygon, const Vector2& centroid,
bool isPenumbra, const char* name) {
float maxAngle = FLT_MIN;
int maxAngleIndex = 0;
for (int i = 0; i < polyLength; i++) {
float currentAngle = angle(polygon[i], centroid);
if (currentAngle > maxAngle) {
maxAngle = currentAngle;
maxAngleIndex = i;
}
angleDataList[i].set(currentAngle, isPenumbra, i);
#if DEBUG_SHADOW
ALOGD("%s AngleList i %d %f", name, i, currentAngle);
#endif
}
return maxAngleIndex;
}
/**
* Make sure the polygons are indeed in clockwise order.
*
* Possible reasons to return false: 1. The input polygon is not setup properly. 2. The hull
* algorithm is not able to generate it properly.
*
* Anyway, since the algorithm depends on the clockwise, when these kind of unexpected error
* situation is found, we need to detect it and early return without corrupting the memory.
*
* @return bool True if the angle list is actually from big to small.
*/
bool SpotShadow::checkClockwise(int indexOfMaxAngle, int listLength, VertexAngleData* angleList,
const char* name) {
int currentIndex = indexOfMaxAngle;
#if DEBUG_SHADOW
ALOGD("max index %d", currentIndex);
#endif
for (int i = 0; i < listLength - 1; i++) {
// TODO: Cache the last angle.
float currentAngle = angleList[currentIndex].mAngle;
float nextAngle = angleList[(currentIndex + 1) % listLength].mAngle;
if (currentAngle < nextAngle) {
#if DEBUG_SHADOW
ALOGE("%s, is not CW, at index %d", name, currentIndex);
#endif
return false;
}
currentIndex = (currentIndex + 1) % listLength;
}
return true;
}
/**
* Check the polygon is clockwise.
*
* @return bool True is the polygon is clockwise.
*/
bool SpotShadow::checkPolyClockwise(int polyAngleLength, int maxPolyAngleIndex,
const float* polyAngleList) {
bool isPolyCW = true;
// Starting from maxPolyAngleIndex , check around to make sure angle decrease.
for (int i = 0; i < polyAngleLength - 1; i++) {
float currentAngle = polyAngleList[(i + maxPolyAngleIndex) % polyAngleLength];
float nextAngle = polyAngleList[(i + maxPolyAngleIndex + 1) % polyAngleLength];
if (currentAngle < nextAngle) {
isPolyCW = false;
}
}
return isPolyCW;
}
/**
* Given the sorted array of all the vertices angle data, calculate for each
* vertices, the offset value to array element which represent the start edge
* of the polygon we need to shoot the ray at.
*
* TODO: Calculate this for umbra and penumbra in one loop using one single array.
*
* @param distances The result of the array distance counter.
*/
void SpotShadow::calculateDistanceCounter(bool needsOffsetToUmbra, int angleLength,
const VertexAngleData* allVerticesAngleData, int* distances) {
bool firstVertexIsPenumbra = allVerticesAngleData[0].mIsPenumbra;
// If we want distance to inner, then we just set to 0 when we see inner.
bool needsSearch = needsOffsetToUmbra ? firstVertexIsPenumbra : !firstVertexIsPenumbra;
int distanceCounter = 0;
if (needsSearch) {
int foundIndex = -1;
for (int i = (angleLength - 1); i >= 0; i--) {
bool currentIsOuter = allVerticesAngleData[i].mIsPenumbra;
// If we need distance to inner, then we need to find a inner vertex.
if (currentIsOuter != firstVertexIsPenumbra) {
foundIndex = i;
break;
}
}
LOG_ALWAYS_FATAL_IF(foundIndex == -1, "Wrong index found, means either"
" umbra or penumbra's length is 0");
distanceCounter = angleLength - foundIndex;
}
#if DEBUG_SHADOW
ALOGD("distances[0] is %d", distanceCounter);
#endif
distances[0] = distanceCounter; // means never see a target poly
for (int i = 1; i < angleLength; i++) {
bool firstVertexIsPenumbra = allVerticesAngleData[i].mIsPenumbra;
// When we needs for distance for each outer vertex to inner, then we
// increase the distance when seeing outer vertices. Otherwise, we clear
// to 0.
bool needsIncrement = needsOffsetToUmbra ? firstVertexIsPenumbra : !firstVertexIsPenumbra;
// If counter is not -1, that means we have seen an other polygon's vertex.
if (needsIncrement && distanceCounter != -1) {
distanceCounter++;
} else {
distanceCounter = 0;
}
distances[i] = distanceCounter;
}
}
/**
* Given umbra and penumbra angle data list, merge them by sorting the angle
* from the biggest to smallest.
*
* @param allVerticesAngleData The result array of merged angle data.
*/
void SpotShadow::mergeAngleList(int maxUmbraAngleIndex, int maxPenumbraAngleIndex,
const VertexAngleData* umbraAngleList, int umbraLength,
const VertexAngleData* penumbraAngleList, int penumbraLength,
VertexAngleData* allVerticesAngleData) {
int totalRayNumber = umbraLength + penumbraLength;
int umbraIndex = maxUmbraAngleIndex;
int penumbraIndex = maxPenumbraAngleIndex;
float currentUmbraAngle = umbraAngleList[umbraIndex].mAngle;
float currentPenumbraAngle = penumbraAngleList[penumbraIndex].mAngle;
// TODO: Clean this up using a while loop with 2 iterators.
for (int i = 0; i < totalRayNumber; i++) {
if (currentUmbraAngle > currentPenumbraAngle) {
allVerticesAngleData[i] = umbraAngleList[umbraIndex];
umbraIndex = (umbraIndex + 1) % umbraLength;
// If umbraIndex round back, that means we are running out of
// umbra vertices to merge, so just copy all the penumbra leftover.
// Otherwise, we update the currentUmbraAngle.
if (umbraIndex != maxUmbraAngleIndex) {
currentUmbraAngle = umbraAngleList[umbraIndex].mAngle;
} else {
for (int j = i + 1; j < totalRayNumber; j++) {
allVerticesAngleData[j] = penumbraAngleList[penumbraIndex];
penumbraIndex = (penumbraIndex + 1) % penumbraLength;
}
break;
}
} else {
allVerticesAngleData[i] = penumbraAngleList[penumbraIndex];
penumbraIndex = (penumbraIndex + 1) % penumbraLength;
// If penumbraIndex round back, that means we are running out of
// penumbra vertices to merge, so just copy all the umbra leftover.
// Otherwise, we update the currentPenumbraAngle.
if (penumbraIndex != maxPenumbraAngleIndex) {
currentPenumbraAngle = penumbraAngleList[penumbraIndex].mAngle;
} else {
for (int j = i + 1; j < totalRayNumber; j++) {
allVerticesAngleData[j] = umbraAngleList[umbraIndex];
umbraIndex = (umbraIndex + 1) % umbraLength;
}
break;
}
}
}
}
#if DEBUG_SHADOW
/**
* DEBUG ONLY: Verify all the offset compuation is correctly done by examining
* each vertex and its neighbor.
*/
static void verifyDistanceCounter(const VertexAngleData* allVerticesAngleData,
const int* distances, int angleLength, const char* name) {
int currentDistance = distances[0];
for (int i = 1; i < angleLength; i++) {
if (distances[i] != INT_MIN) {
if (!((currentDistance + 1) == distances[i]
|| distances[i] == 0)) {
ALOGE("Wrong distance found at i %d name %s", i, name);
}
currentDistance = distances[i];
if (currentDistance != 0) {
bool currentOuter = allVerticesAngleData[i].mIsPenumbra;
for (int j = 1; j <= (currentDistance - 1); j++) {
bool neigborOuter =
allVerticesAngleData[(i + angleLength - j) % angleLength].mIsPenumbra;
if (neigborOuter != currentOuter) {
ALOGE("Wrong distance found at i %d name %s", i, name);
}
}
bool oppositeOuter =
allVerticesAngleData[(i + angleLength - currentDistance) % angleLength].mIsPenumbra;
if (oppositeOuter == currentOuter) {
ALOGE("Wrong distance found at i %d name %s", i, name);
}
}
}
}
}
/**
* DEBUG ONLY: Verify all the angle data compuated are is correctly done
*/
static void verifyAngleData(int totalRayNumber, const VertexAngleData* allVerticesAngleData,
const int* distancesToInner, const int* distancesToOuter,
const VertexAngleData* umbraAngleList, int maxUmbraAngleIndex, int umbraLength,
const VertexAngleData* penumbraAngleList, int maxPenumbraAngleIndex,
int penumbraLength) {
for (int i = 0; i < totalRayNumber; i++) {
ALOGD("currentAngleList i %d, angle %f, isInner %d, index %d distancesToInner"
" %d distancesToOuter %d", i, allVerticesAngleData[i].mAngle,
!allVerticesAngleData[i].mIsPenumbra,
allVerticesAngleData[i].mVertexIndex, distancesToInner[i], distancesToOuter[i]);
}
verifyDistanceCounter(allVerticesAngleData, distancesToInner, totalRayNumber, "distancesToInner");
verifyDistanceCounter(allVerticesAngleData, distancesToOuter, totalRayNumber, "distancesToOuter");
for (int i = 0; i < totalRayNumber; i++) {
if ((distancesToInner[i] * distancesToOuter[i]) != 0) {
ALOGE("distancesToInner wrong at index %d distancesToInner[i] %d,"
" distancesToOuter[i] %d", i, distancesToInner[i], distancesToOuter[i]);
}
}
int currentUmbraVertexIndex =
umbraAngleList[maxUmbraAngleIndex].mVertexIndex;
int currentPenumbraVertexIndex =
penumbraAngleList[maxPenumbraAngleIndex].mVertexIndex;
for (int i = 0; i < totalRayNumber; i++) {
if (allVerticesAngleData[i].mIsPenumbra == true) {
if (allVerticesAngleData[i].mVertexIndex != currentPenumbraVertexIndex) {
ALOGW("wrong penumbra indexing i %d allVerticesAngleData[i].mVertexIndex %d "
"currentpenumbraVertexIndex %d", i,
allVerticesAngleData[i].mVertexIndex, currentPenumbraVertexIndex);
}
currentPenumbraVertexIndex = (currentPenumbraVertexIndex + 1) % penumbraLength;
} else {
if (allVerticesAngleData[i].mVertexIndex != currentUmbraVertexIndex) {
ALOGW("wrong umbra indexing i %d allVerticesAngleData[i].mVertexIndex %d "
"currentUmbraVertexIndex %d", i,
allVerticesAngleData[i].mVertexIndex, currentUmbraVertexIndex);
}
currentUmbraVertexIndex = (currentUmbraVertexIndex + 1) % umbraLength;
}
}
for (int i = 0; i < totalRayNumber - 1; i++) {
float currentAngle = allVerticesAngleData[i].mAngle;
float nextAngle = allVerticesAngleData[(i + 1) % totalRayNumber].mAngle;
if (currentAngle < nextAngle) {
ALOGE("Unexpected angle values!, currentAngle nextAngle %f %f", currentAngle, nextAngle);
}
}
}
#endif
/**
* In order to compute the occluded umbra, we need to setup the angle data list
* for the polygon data. Since we only store one poly vertex per polygon vertex,
* this array only needs to be a float array which are the angles for each vertex.
*
* @param polyAngleList The result list
*
* @return int The index for the maximum angle in this array.
*/
int SpotShadow::setupPolyAngleList(float* polyAngleList, int polyAngleLength,
const Vector2* poly2d, const Vector2& centroid) {
int maxPolyAngleIndex = -1;
float maxPolyAngle = -FLT_MAX;
for (int i = 0; i < polyAngleLength; i++) {
polyAngleList[i] = angle(poly2d[i], centroid);
if (polyAngleList[i] > maxPolyAngle) {
maxPolyAngle = polyAngleList[i];
maxPolyAngleIndex = i;
}
}
return maxPolyAngleIndex;
}
/**
* For umbra and penumbra, given the offset info and the current ray number,
* find the right edge index (the (starting vertex) for the ray to shoot at.
*
* @return int The index of the starting vertex of the edge.
*/
inline int SpotShadow::getEdgeStartIndex(const int* offsets, int rayIndex, int totalRayNumber,
const VertexAngleData* allVerticesAngleData) {
int tempOffset = offsets[rayIndex];
int targetRayIndex = (rayIndex - tempOffset + totalRayNumber) % totalRayNumber;
return allVerticesAngleData[targetRayIndex].mVertexIndex;
}
/**
* For the occluded umbra, given the array of angles, find the index of the
* starting vertex of the edge, for the ray to shoo at.
*
* TODO: Save the last result to shorten the search distance.
*
* @return int The index of the starting vertex of the edge.
*/
inline int SpotShadow::getPolyEdgeStartIndex(int maxPolyAngleIndex, int polyLength,
const float* polyAngleList, float rayAngle) {
int minPolyAngleIndex = (maxPolyAngleIndex + polyLength - 1) % polyLength;
int resultIndex = -1;
if (rayAngle > polyAngleList[maxPolyAngleIndex]
|| rayAngle <= polyAngleList[minPolyAngleIndex]) {
resultIndex = minPolyAngleIndex;
} else {
for (int i = 0; i < polyLength - 1; i++) {
int currentIndex = (maxPolyAngleIndex + i) % polyLength;
int nextIndex = (maxPolyAngleIndex + i + 1) % polyLength;
if (rayAngle <= polyAngleList[currentIndex]
&& rayAngle > polyAngleList[nextIndex]) {
resultIndex = currentIndex;
}
}
}
if (CC_UNLIKELY(resultIndex == -1)) {
// TODO: Add more error handling here.
ALOGE("Wrong index found, means no edge can't be found for rayAngle %f", rayAngle);
}
return resultIndex;
}
/**
* Convert the incoming polygons into arrays of vertices, for each ray.
* Ray only shoots when there is one vertex either on penumbra on umbra.
*
* Finally, it will generate vertices per ray for umbra, penumbra and optionally
* occludedUmbra.
*
* Return true (success) when all vertices are generated
*/
int SpotShadow::convertPolysToVerticesPerRay(
bool hasOccludedUmbraArea, const Vector2* poly2d, int polyLength,
const Vector2* umbra, int umbraLength, const Vector2* penumbra,
int penumbraLength, const Vector2& centroid,
Vector2* umbraVerticesPerRay, Vector2* penumbraVerticesPerRay,
Vector2* occludedUmbraVerticesPerRay) {
int totalRayNumber = umbraLength + penumbraLength;
// For incoming umbra / penumbra polygons, we will build an intermediate data
// structure to help us sort all the vertices according to the vertices.
// Using this data structure, we can tell where (the angle) to shoot the ray,
// whether we shoot at penumbra edge or umbra edge, and which edge to shoot at.
//
// We first parse each vertices and generate a table of VertexAngleData.
// Based on that, we create 2 arrays telling us which edge to shoot at.
VertexAngleData allVerticesAngleData[totalRayNumber];
VertexAngleData umbraAngleList[umbraLength];
VertexAngleData penumbraAngleList[penumbraLength];
int polyAngleLength = hasOccludedUmbraArea ? polyLength : 0;
float polyAngleList[polyAngleLength];
const int maxUmbraAngleIndex =
setupAngleList(umbraAngleList, umbraLength, umbra, centroid, false, "umbra");
const int maxPenumbraAngleIndex =
setupAngleList(penumbraAngleList, penumbraLength, penumbra, centroid, true, "penumbra");
const int maxPolyAngleIndex = setupPolyAngleList(polyAngleList, polyAngleLength, poly2d, centroid);
// Check all the polygons here are CW.
bool isPolyCW = checkPolyClockwise(polyAngleLength, maxPolyAngleIndex, polyAngleList);
bool isUmbraCW = checkClockwise(maxUmbraAngleIndex, umbraLength,
umbraAngleList, "umbra");
bool isPenumbraCW = checkClockwise(maxPenumbraAngleIndex, penumbraLength,
penumbraAngleList, "penumbra");
if (!isUmbraCW || !isPenumbraCW || !isPolyCW) {
#if DEBUG_SHADOW
ALOGE("One polygon is not CW isUmbraCW %d isPenumbraCW %d isPolyCW %d",
isUmbraCW, isPenumbraCW, isPolyCW);
#endif
return false;
}
mergeAngleList(maxUmbraAngleIndex, maxPenumbraAngleIndex,
umbraAngleList, umbraLength, penumbraAngleList, penumbraLength,
allVerticesAngleData);
// Calculate the offset to the left most Inner vertex for each outerVertex.
// Then the offset to the left most Outer vertex for each innerVertex.
int offsetToInner[totalRayNumber];
int offsetToOuter[totalRayNumber];
calculateDistanceCounter(true, totalRayNumber, allVerticesAngleData, offsetToInner);
calculateDistanceCounter(false, totalRayNumber, allVerticesAngleData, offsetToOuter);
// Generate both umbraVerticesPerRay and penumbraVerticesPerRay
for (int i = 0; i < totalRayNumber; i++) {
float rayAngle = allVerticesAngleData[i].mAngle;
bool isUmbraVertex = !allVerticesAngleData[i].mIsPenumbra;
float dx = cosf(rayAngle);
float dy = sinf(rayAngle);
float distanceToIntersectUmbra = -1;
if (isUmbraVertex) {
// We can just copy umbra easily, and calculate the distance for the
// occluded umbra computation.
int startUmbraIndex = allVerticesAngleData[i].mVertexIndex;
umbraVerticesPerRay[i] = umbra[startUmbraIndex];
if (hasOccludedUmbraArea) {
distanceToIntersectUmbra = (umbraVerticesPerRay[i] - centroid).length();
}
//shoot ray to penumbra only
int startPenumbraIndex = getEdgeStartIndex(offsetToOuter, i, totalRayNumber,
allVerticesAngleData);
float distanceToIntersectPenumbra = rayIntersectPoints(centroid, dx, dy,
penumbra[startPenumbraIndex],
penumbra[(startPenumbraIndex + 1) % penumbraLength]);
if (distanceToIntersectPenumbra < 0) {
#if DEBUG_SHADOW
ALOGW("convertPolyToRayDist for penumbra failed rayAngle %f dx %f dy %f",
rayAngle, dx, dy);
#endif
distanceToIntersectPenumbra = 0;
}
penumbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectPenumbra;
penumbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectPenumbra;
} else {
// We can just copy the penumbra
int startPenumbraIndex = allVerticesAngleData[i].mVertexIndex;
penumbraVerticesPerRay[i] = penumbra[startPenumbraIndex];
// And shoot ray to umbra only
int startUmbraIndex = getEdgeStartIndex(offsetToInner, i, totalRayNumber,
allVerticesAngleData);
distanceToIntersectUmbra = rayIntersectPoints(centroid, dx, dy,
umbra[startUmbraIndex], umbra[(startUmbraIndex + 1) % umbraLength]);
if (distanceToIntersectUmbra < 0) {
#if DEBUG_SHADOW
ALOGW("convertPolyToRayDist for umbra failed rayAngle %f dx %f dy %f",
rayAngle, dx, dy);
#endif
distanceToIntersectUmbra = 0;
}
umbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectUmbra;
umbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectUmbra;
}
if (hasOccludedUmbraArea) {
// Shoot the same ray to the poly2d, and get the distance.
int startPolyIndex = getPolyEdgeStartIndex(maxPolyAngleIndex, polyLength,
polyAngleList, rayAngle);
float distanceToIntersectPoly = rayIntersectPoints(centroid, dx, dy,
poly2d[startPolyIndex], poly2d[(startPolyIndex + 1) % polyLength]);
if (distanceToIntersectPoly < 0) {
distanceToIntersectPoly = 0;
}
distanceToIntersectPoly = MathUtils::min(distanceToIntersectUmbra, distanceToIntersectPoly);
occludedUmbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectPoly;
occludedUmbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectPoly;
}
}
#if DEBUG_SHADOW
verifyAngleData(totalRayNumber, allVerticesAngleData, offsetToInner,
offsetToOuter, umbraAngleList, maxUmbraAngleIndex, umbraLength,
penumbraAngleList, maxPenumbraAngleIndex, penumbraLength);
#endif
return true; // success
}
/**
* Generate a triangle strip given two convex polygon
**/
void SpotShadow::generateTriangleStrip(bool isCasterOpaque, float shadowStrengthScale,
Vector2* penumbra, int penumbraLength, Vector2* umbra, int umbraLength,
const Vector3* poly, int polyLength, VertexBuffer& shadowTriangleStrip,
const Vector2& centroid) {
bool hasOccludedUmbraArea = false;
Vector2 poly2d[polyLength];
if (isCasterOpaque) {
for (int i = 0; i < polyLength; i++) {
poly2d[i].x = poly[i].x;
poly2d[i].y = poly[i].y;
}
// Make sure the centroid is inside the umbra, otherwise, fall back to the
// approach as if there is no occluded umbra area.
if (testPointInsidePolygon(centroid, poly2d, polyLength)) {
hasOccludedUmbraArea = true;
}
}
int totalRayNum = umbraLength + penumbraLength;
Vector2 umbraVertices[totalRayNum];
Vector2 penumbraVertices[totalRayNum];
Vector2 occludedUmbraVertices[totalRayNum];
bool convertSuccess = convertPolysToVerticesPerRay(hasOccludedUmbraArea, poly2d,
polyLength, umbra, umbraLength, penumbra, penumbraLength,
centroid, umbraVertices, penumbraVertices, occludedUmbraVertices);
if (!convertSuccess) {
return;
}
// Minimal value is 1, for each vertex show up once.
// The bigger this value is , the smoother the look is, but more memory
// is consumed.
// When the ray number is high, that means the polygon has been fine
// tessellated, we don't need this extra slice, just keep it as 1.
int sliceNumberPerEdge = (totalRayNum > FINE_TESSELLATED_POLYGON_RAY_NUMBER) ? 1 : 2;
// For each polygon, we at most add (totalRayNum * sliceNumberPerEdge) vertices.
int slicedVertexCountPerPolygon = totalRayNum * sliceNumberPerEdge;
int totalVertexCount = slicedVertexCountPerPolygon * 2 + totalRayNum;
int totalIndexCount = 2 * (slicedVertexCountPerPolygon * 2 + 2);
AlphaVertex* shadowVertices =
shadowTriangleStrip.alloc<AlphaVertex>(totalVertexCount);
uint16_t* indexBuffer =
shadowTriangleStrip.allocIndices<uint16_t>(totalIndexCount);
int indexBufferIndex = 0;
int vertexBufferIndex = 0;
uint16_t slicedUmbraVertexIndex[totalRayNum * sliceNumberPerEdge];
// Should be something like 0 0 0 1 1 1 2 3 3 3...
int rayNumberPerSlicedUmbra[totalRayNum * sliceNumberPerEdge];
int realUmbraVertexCount = 0;
for (int i = 0; i < totalRayNum; i++) {
Vector2 currentPenumbra = penumbraVertices[i];
Vector2 currentUmbra = umbraVertices[i];
Vector2 nextPenumbra = penumbraVertices[(i + 1) % totalRayNum];
Vector2 nextUmbra = umbraVertices[(i + 1) % totalRayNum];
// NextUmbra/Penumbra will be done in the next loop!!
for (int weight = 0; weight < sliceNumberPerEdge; weight++) {
const Vector2& slicedPenumbra = (currentPenumbra * (sliceNumberPerEdge - weight)
+ nextPenumbra * weight) / sliceNumberPerEdge;
const Vector2& slicedUmbra = (currentUmbra * (sliceNumberPerEdge - weight)
+ nextUmbra * weight) / sliceNumberPerEdge;
// In the vertex buffer, we fill the Penumbra first, then umbra.
indexBuffer[indexBufferIndex++] = vertexBufferIndex;
AlphaVertex::set(&shadowVertices[vertexBufferIndex++], slicedPenumbra.x,
slicedPenumbra.y, 0.0f);
// When we add umbra vertex, we need to remember its current ray number.
// And its own vertexBufferIndex. This is for occluded umbra usage.
indexBuffer[indexBufferIndex++] = vertexBufferIndex;
rayNumberPerSlicedUmbra[realUmbraVertexCount] = i;
slicedUmbraVertexIndex[realUmbraVertexCount] = vertexBufferIndex;
realUmbraVertexCount++;
AlphaVertex::set(&shadowVertices[vertexBufferIndex++], slicedUmbra.x,
slicedUmbra.y, M_PI);
}
}
indexBuffer[indexBufferIndex++] = 0;
//RealUmbraVertexIndex[0] must be 1, so we connect back well at the
//beginning of occluded area.
indexBuffer[indexBufferIndex++] = 1;
float occludedUmbraAlpha = M_PI;
if (hasOccludedUmbraArea) {
// Now the occludedUmbra area;
int currentRayNumber = -1;
int firstOccludedUmbraIndex = -1;
for (int i = 0; i < realUmbraVertexCount; i++) {
indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[i];
// If the occludedUmbra vertex has not been added yet, then add it.
// Otherwise, just use the previously added occludedUmbra vertices.
if (rayNumberPerSlicedUmbra[i] != currentRayNumber) {
currentRayNumber++;
indexBuffer[indexBufferIndex++] = vertexBufferIndex;
// We need to remember the begining of the occludedUmbra vertices
// to close this loop.
if (currentRayNumber == 0) {
firstOccludedUmbraIndex = vertexBufferIndex;
}
AlphaVertex::set(&shadowVertices[vertexBufferIndex++],
occludedUmbraVertices[currentRayNumber].x,
occludedUmbraVertices[currentRayNumber].y,
occludedUmbraAlpha);
} else {
indexBuffer[indexBufferIndex++] = (vertexBufferIndex - 1);
}
}
// Close the loop here!
indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[0];
indexBuffer[indexBufferIndex++] = firstOccludedUmbraIndex;
} else {
int lastCentroidIndex = vertexBufferIndex;
AlphaVertex::set(&shadowVertices[vertexBufferIndex++], centroid.x,
centroid.y, occludedUmbraAlpha);
for (int i = 0; i < realUmbraVertexCount; i++) {
indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[i];
indexBuffer[indexBufferIndex++] = lastCentroidIndex;
}
// Close the loop here!
indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[0];
indexBuffer[indexBufferIndex++] = lastCentroidIndex;
}
#if DEBUG_SHADOW
ALOGD("allocated IB %d allocated VB is %d", totalIndexCount, totalVertexCount);
ALOGD("IB index %d VB index is %d", indexBufferIndex, vertexBufferIndex);
for (int i = 0; i < vertexBufferIndex; i++) {
ALOGD("vertexBuffer i %d, (%f, %f %f)", i, shadowVertices[i].x, shadowVertices[i].y,
shadowVertices[i].alpha);
}
for (int i = 0; i < indexBufferIndex; i++) {
ALOGD("indexBuffer i %d, indexBuffer[i] %d", i, indexBuffer[i]);
}
#endif
// At the end, update the real index and vertex buffer size.
shadowTriangleStrip.updateVertexCount(vertexBufferIndex);
shadowTriangleStrip.updateIndexCount(indexBufferIndex);
ShadowTessellator::checkOverflow(vertexBufferIndex, totalVertexCount, "Spot Vertex Buffer");
ShadowTessellator::checkOverflow(indexBufferIndex, totalIndexCount, "Spot Index Buffer");
shadowTriangleStrip.setMode(VertexBuffer::kIndices);
shadowTriangleStrip.computeBounds<AlphaVertex>();
}
#if DEBUG_SHADOW
#define TEST_POINT_NUMBER 128
/**
* Calculate the bounds for generating random test points.
*/
void SpotShadow::updateBound(const Vector2 inVector, Vector2& lowerBound,
Vector2& upperBound) {
if (inVector.x < lowerBound.x) {
lowerBound.x = inVector.x;
}
if (inVector.y < lowerBound.y) {
lowerBound.y = inVector.y;
}
if (inVector.x > upperBound.x) {
upperBound.x = inVector.x;
}
if (inVector.y > upperBound.y) {
upperBound.y = inVector.y;
}
}
/**
* For debug purpose, when things go wrong, dump the whole polygon data.
*/
void SpotShadow::dumpPolygon(const Vector2* poly, int polyLength, const char* polyName) {
for (int i = 0; i < polyLength; i++) {
ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y);
}
}
/**
* For debug purpose, when things go wrong, dump the whole polygon data.
*/
void SpotShadow::dumpPolygon(const Vector3* poly, int polyLength, const char* polyName) {
for (int i = 0; i < polyLength; i++) {
ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y);
}
}
/**
* Test whether the polygon is convex.
*/
bool SpotShadow::testConvex(const Vector2* polygon, int polygonLength,
const char* name) {
bool isConvex = true;
for (int i = 0; i < polygonLength; i++) {
Vector2 start = polygon[i];
Vector2 middle = polygon[(i + 1) % polygonLength];
Vector2 end = polygon[(i + 2) % polygonLength];
double delta = (double(middle.x) - start.x) * (double(end.y) - start.y) -
(double(middle.y) - start.y) * (double(end.x) - start.x);
bool isCCWOrCoLinear = (delta >= EPSILON);
if (isCCWOrCoLinear) {
ALOGW("(Error Type 2): polygon (%s) is not a convex b/c start (x %f, y %f),"
"middle (x %f, y %f) and end (x %f, y %f) , delta is %f !!!",
name, start.x, start.y, middle.x, middle.y, end.x, end.y, delta);
isConvex = false;
break;
}
}
return isConvex;
}
/**
* Test whether or not the polygon (intersection) is within the 2 input polygons.
* Using Marte Carlo method, we generate a random point, and if it is inside the
* intersection, then it must be inside both source polygons.
*/
void SpotShadow::testIntersection(const Vector2* poly1, int poly1Length,
const Vector2* poly2, int poly2Length,
const Vector2* intersection, int intersectionLength) {
// Find the min and max of x and y.
Vector2 lowerBound = {FLT_MAX, FLT_MAX};
Vector2 upperBound = {-FLT_MAX, -FLT_MAX};
for (int i = 0; i < poly1Length; i++) {
updateBound(poly1[i], lowerBound, upperBound);
}
for (int i = 0; i < poly2Length; i++) {
updateBound(poly2[i], lowerBound, upperBound);
}
bool dumpPoly = false;
for (int k = 0; k < TEST_POINT_NUMBER; k++) {
// Generate a random point between minX, minY and maxX, maxY.
double randomX = rand() / double(RAND_MAX);
double randomY = rand() / double(RAND_MAX);
Vector2 testPoint;
testPoint.x = lowerBound.x + randomX * (upperBound.x - lowerBound.x);
testPoint.y = lowerBound.y + randomY * (upperBound.y - lowerBound.y);
// If the random point is in both poly 1 and 2, then it must be intersection.
if (testPointInsidePolygon(testPoint, intersection, intersectionLength)) {
if (!testPointInsidePolygon(testPoint, poly1, poly1Length)) {
dumpPoly = true;
ALOGW("(Error Type 1): one point (%f, %f) in the intersection is"
" not in the poly1",
testPoint.x, testPoint.y);
}
if (!testPointInsidePolygon(testPoint, poly2, poly2Length)) {
dumpPoly = true;
ALOGW("(Error Type 1): one point (%f, %f) in the intersection is"
" not in the poly2",
testPoint.x, testPoint.y);
}
}
}
if (dumpPoly) {
dumpPolygon(intersection, intersectionLength, "intersection");
for (int i = 1; i < intersectionLength; i++) {
Vector2 delta = intersection[i] - intersection[i - 1];
ALOGD("Intersetion i, %d Vs i-1 is delta %f", i, delta.lengthSquared());
}
dumpPolygon(poly1, poly1Length, "poly 1");
dumpPolygon(poly2, poly2Length, "poly 2");
}
}
#endif
}; // namespace uirenderer
}; // namespace android